use crate::buffer::{
pool,
pool::{borrowed, state},
};
pub struct Source<'pool> {
pool: &'pool pool::Pool<state::Initialized>,
start: u32,
end: u32,
}
impl<'pool> Source<'pool> {
pub fn try_new(
pool: &'pool pool::Pool<state::Initialized>,
length: usize,
suffix: usize,
) -> Result<Self, borrowed::Error> {
let capacity = pool.capacity();
let error = borrowed::Error::Capacity {
length,
suffix,
capacity,
};
let end = (capacity.get() as usize).checked_sub(suffix).ok_or(error)?;
let start = end.checked_sub(length).ok_or(error)?;
Ok(Self {
pool,
start: start as u32,
end: end as u32,
})
}
pub fn is_empty(&self) -> bool {
self.len() == 0
}
pub fn len(&self) -> usize {
(self.end - self.start) as usize
}
pub fn into_split(self) -> borrowed::Split<'pool> {
borrowed::Split {
source: self,
suffix: 0,
}
}
pub fn acquire(&self) -> Option<borrowed::Slice<'pool>> {
let span = pool::Span::borrow(&self.pool.core)?;
Some(borrowed::Slice {
span,
start: self.start,
end: self.end,
})
}
}
const _: () = assert!(size_of::<Source<'static>>() == 2 * size_of::<usize>());